1. Field of the Invention
The present invention relates to closable air-tight plastic bags which have a one-way air valve for exhausting air after the bag is closed. It particularly, though not exclusively, relates to resealable air-tight food storage-type bags having a one-way air exhausting valve.
2. Discussion of the Prior Art
Closable plastic bags, particularly those known as food storage bags, are widely used to preserve food. Such bags usually have a closure member for securely and, in many instances, air-tightly closing the bag. One example of an air-tight closure is that used in the Zip-loc storage bag, which is illustrated in U.S. Reissue Pat. No. 28,969. Another type of sandwich bag having an air-tight closure is illustrated in co-pending U.S. Patent Application Ser. No. 433,588 filed Oct. 12, 1982.
While air-tight closures are preferred to maintain food freshness, it is difficult to exhaust air from the bags upon closure. At present, a user must coordinate his movements so that the food-filled bag is first substantially, but not completely, closed, then air-exhausted by pressing the air from the bag and then completely closed before a substantial amount of air re-enters the bag. The movements required are cumbersome and are not easily performed by those lacking a high degree of dexterity and coordination. Accordingly, the bag is often not air-exhausted to the extent it could be or is not air-exhausted at all, which decreases the ability of the sealed bag to maintain food freshness.
When larger high strength bags are used in industrial applications, entrapped air in a filled bag distorts the bag shape, making transportation and storage of filled bags difficult. Entrapped air may also affect the bag contents.